[Breaking] Bump sass-loader to v16 (#84387)
This PR bumps sass-loader to v16 as Sass is deprecating the legacy JS
API, and updating sass-loader ensures compatibility with future Sass
versions.
x-ref: https://github.com/vercel/next.js/discussions/67931
This removes the silencing of the deprecation warning added at
https://github.com/vercel/next.js/pull/72632.
Supersedes https://github.com/vercel/next.js/pull/83091
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Co-authored-by: Maikel <maikel.van.dort@gmail.com>
